<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Title</title>
    <style>
        /*#wrap ul li {*/
        /*width: 100px;*/
        /*height: 100px;*/
        /*border: 1px solid red;*/
        /*}*/

        /*#wrap ol li {*/
        /*width: 100px;*/
        /*height: 100px;*/
        /*border: 1px solid blue;*/
        /*}*/

        /*#wrap li{*/
        /*width: 100px;*/
        /*height: 50px;*/
        /*border: 1px solid red;*/
        /*}*/

        #wrap li.blue {
            width: 100px;
            height: 50px;
            border: 1px solid blue;
        }
    </style>
</head>
<body>
<div id="wrap">
    <ul>
        <li>red</li>
    </ul>
    <ol>
        <li>green</li>
    </ol>
    <ul>
        <li class="blue">blue</li>
    </ul>
</div>
</body>
</html>